Reactions of Amines with Ketones and Aldehydes Review

Reactions of Amines with Ketones and Aldehydes (Review) 

In contrast to other functional groups, we will study the reactions of amines before we study their syntheses. This approach is better because most amine syntheses begin with an amine (or ammonia) and add groups to make more-substituted amines. In other words, most amine syntheses involve the reactions of amines. By studying the reactions first, we can readily understand how to use these reactions to convert simpler amines to more complicated amines. 

In Section 18-16, we saw that amines attack ketones and aldehydes. When this nucleophilic attack is followed by dehydration, an imine (Schiff base) results. The analogous reaction of a hydrazine derivative gives a hydrazone, and the reaction with hydroxylamine gives an oxime. In Section 19-19, we will use these reactions to synthesize amines. 

In an arylamine, the nonbonding electrons on nitrogen help stabilize intermediates result- 

The following reactions show halogenation of aniline derivatives, which occurs readily without a catalyst. If an excess of the reagent is used, all the unsubstituted positions ortho and para to the amino group become substituted. 

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